1. Field of the Invention
The present invention relates generally to an apparatus employed in manufacture of semiconductor modules. More particularly, the present invention relates to an apparatus for carrying multiple printed circuit boards during a process of manufacturing semiconductor modules.
2. Description of the Prior Art
As electronic devices become more complex and employ more integrated circuits, it is desirable, if possible, to avoid increasing the space where they occupy. To solve this problem, modules mounted with plural integrated circuit devices have been employed. In a typical module, the integrated circuit devices, for example, semiconductor packages, are attached to one side or both sides of a printed circuit board (PCB).
For higher productivity, modules are generally produced in a production line where PCBs move along conveyor belt. In particular, sheet-type PCBs are subjected to the manufacturing process of the module, as well known in the art. Each sheet-type PCB has a number of individual PCBs, what are called piece-type PCBs, which are linked with each other at their ends, leaving central isolated space between adjacent individual PCBs. A final module product, which includes a single individual PCB, is obtained by cutting the link part of the sheet-type PCBs after completing the processing of the sheet-type PCBs.
However, the use of the sheet-type PCBs raises some problems. One of them is that the sheet-type PCBs have several wasted parts, such as link part or space. These wasted parts are required to hold the sheet-type during the manufacturing process, but not required by final product. Moreover, although unexpected failures may be found from one or more among the individual PCBs of a sheet-type PCB during the manufacturing process, the failed individual PCBs are still subjected to the final steps of process because of difficulty of removing the failed PCBs before completion of the process. This is a significant drawback in light of productivity.
Accordingly, in recent years, multiple individual PCBs without link parts or space are separated at the beginning of the manufacturing process of the modules. This provides lower per PCB cost than the above-described sheet-type PCB processing since the absence of link parts or space reduces the required amount of raw PCB material. A jig carrier makes this improvement possible. The jig carrier can not only carries a large quantity of individual PCBs, but also ensures better productivity than the sheet-type PCB processing.
FIG. 1 is a perspective view of an existing jig carrier 10 as a conventional apparatus for carrying PCBs 20 for semiconductor modules; and FIG. 2 is a perspective view for schematically showing a typical PCB 20 for a semiconductor module.
As shown in FIGS. 1 and 2, the prior jig carrier 10 comprises a rectangular frame 12 and two opposite plates 14 inside the frame 12. Pins 16 are formed at regular intervals on the plates 14. The PCB 20 is a rectangular panel having two opposite shorter edges 21 and two opposite longer edges 22. The PCB 20 has a great number of circuit patterns, not shown, formed on both top and bottom surfaces thereof, as widely known in the art. The PCB 20 further includes through holes 26 corresponding to the pins 16 of the jig carrier 10.
When the PCB 20 is on the jig carrier 10, the plates 14 of the jig carrier 10 support the bottom surface of the PCB 20, and the pins 16 are inserted into the through holes 26. After all PCBs 20 are loaded into the jig carrier 10, adhesive tape 18 is stuck to both top surfaces of the PCB 20 and the jig carrier 10, so that the PCB 20 is completely fixed to the jig carrier 10.
Many kinds of PCBs 20 are employed for the modules. There are different sizes for PCBs 20 as well. Accordingly, PCBs of different sizes typically require different jig carriers 10. The use of a particular jig carrier 10 is limited by the fixed size of its frame 12 and the fixed positions of its pins 16. Another disadvantage of the existing jig carrier 10 is that the attaching of the tape 18 and the loading of the PCBs 20 are done manually. In addition, when the module has double-sided devices, the adhesive tapes 18 must be removed from the PCBs 20 and then the PCBs 20 are flipped over for attaching of devices onto the back side of the PCB 20. This manual manipulation of the PCBs can lower productivity of the module manufacturing process.